JP6805728B2 - Energization control system - Google Patents

Description

The present invention relates to a power control system for controlling the energization of the heating element.

Conventionally, a voltage converter that boosts an input voltage to a predetermined voltage when driving a three-phase motor and an inverter that frequency-converts the output of the voltage converter have been used. On the other hand, a plurality of switching elements are used in such a voltage converter or an inverter. These switching elements generate heat by themselves when energized, but their electrical characteristics and ratings are specified according to the ambient temperature of the switching elements. Therefore, when using such a switching element, it is necessary to consider the ambient temperature. As a technique for utilizing a switching element in consideration of such an ambient temperature, for example, there is one described in Patent Document 1.

The electric vehicle described in Patent Document 1 uses an inverter that supplies electric power to a three-phase motor, and the inverter is provided with a plurality of switching elements. This electric vehicle is configured to include a temperature sensor that measures the temperature of the refrigerant that cools the switching element, a current sensor that measures the output current of the inverter, and a voltage sensor that measures the input voltage to the inverter. The temperature correction value is calculated based on the measurement data of the current sensor, the measurement data of the voltage sensor, and the duty ratio of the switching element for each element, and the temperature correction value is added to the measurement result of the temperature of the refrigerant to add the temperature correction value of the switching element. Is estimated.

Japanese Unexamined Patent Publication No. 2013-48515

In the technique described in Patent Document 1, detection results of a plurality of sensors are used for estimating the temperature of the switching element. In this case, since each detection result includes an error, the error included in the estimation result of the temperature of the switching element also becomes large. Therefore, when energizing the switching element, it is necessary to consider the margin with respect to the electrical characteristics and rating. Therefore, the technique described in Patent Document 1 may not be able to fully utilize the capabilities of the switching element.

Therefore, there is a need for an energization control system that can fully utilize the capabilities of switching elements.

The characteristic configuration of the energization control system according to the present invention is that a magnetic detector that detects the magnetic flux density of the magnetic flux generated around the conductor according to the current flowing through the conductor of the electric device and the magnetic detector are arranged. A temperature detector that detects the temperature inside the package, a correction unit that corrects the temperature characteristics included in the detection result of the magnetic detector based on the detected temperature, and temperature information indicating the detected temperature are output. A sensor unit having an output unit, and a control unit having a control unit for controlling a current flowing through a heating element of the electric device based on the temperature information, and the control unit is stored in advance. The temperature of the heating element is estimated based on the map showing the relationship between the temperature information and the temperature rise value of the heating element and the temperature information transmitted from the sensor unit, and the heating element is estimated based on the estimation result. lies in the fact that control of the operation.

With such a characteristic configuration, the measurement of the current flowing through the conductor according to the magnetic flux density detected by the magnetic detector and the measurement of the temperature inside the package provided with the magnetic detector are performed by a single sensor unit. be able to. Therefore, when this current is more than expected, the control unit can limit the current, and of course, the control unit can limit the current even when the temperature rises too much. It becomes. Further, for example, in the case of a configuration in which the current flowing through the conductor is controlled by the switching element, in this energization control system, the switching element is controlled based on the measurement results of the current value and the temperature rise value of the current flowing through the conductor. Therefore, it is possible to control the current using the measurement result with a small error. Therefore, it is possible to fully utilize the capacity of the switching element.

Further, with such a configuration, the control unit can accurately estimate the temperature of the heating element.

Therefore, the ability of the heating element can be fully utilized and damage to the heating element can be prevented.

Further, the conductor electrically connects a three-phase rotary electric machine and a frequency converter that converts at least one of the frequencies of the electric current input to the three-phase rotary electric machine and the electric current output from the three-phase rotary electric machine. The heating element is a plurality of switching elements of the frequency converter, and the control unit is in a state in which the current value of the current flowing through each bus bar is substantially constant for a predetermined time. When it is determined that the current has continued, the bus bar through which the current of the current value indicating the largest value among the current values of the current flowing through each bus bar flows is specified, and the temperature rise of the switching element that controls the current flowing through the specified bus bar. It is preferable to estimate the value based on the temperature information and limit the on-DUTY of the switching element when the estimated temperature rise value is equal to or higher than a preset value.

With such a configuration, it is possible to identify the switching element having the largest temperature rise and control the current flowing through the specified switching element. Therefore, it is possible to prevent an overcurrent from flowing through the switching element while fully utilizing the capacity of the switching element. Therefore, it is possible to prevent damage to the switching element of the frequency converter.

Further, the conductor is connected in series to the output terminal of an inductor of a voltage converter that boosts and outputs a predetermined input voltage, and the heating element is a switching element of the voltage converter and is a control unit. It is preferable to estimate the temperature rise value of the inductor based on the temperature information, and limit the on-DUTY of the switching element when the estimated temperature rise value is equal to or higher than a preset value.

In a voltage converter for boosting, ideally the current flowing through the inductor is the sum of the current flowing through the switching element and the current flowing through the diode. Therefore, in this configuration, by estimating the current value of the current flowing through the switching element according to the temperature rise value of the inductor, the capacity of the switching element of the voltage converter can be fully utilized while the switching element is overloaded. It is possible to prevent the flow of electric current. Therefore, damage to the switching element of the voltage converter can be prevented.

Further, when the temperature inside the package indicated by the temperature information reaches a preset reference temperature, the control unit calculates the magnetic flux related to the magnetic flux density to be detected by the sensor unit that outputs the temperature information. It is preferable to regulate the flow of the generated current.

With such a configuration, the control unit can grasp the heat load status of the magnetic detector unit and reduce the heat load on the magnetic detector unit when the temperature inside the package reaches a preset reference temperature. It will be possible. Therefore, damage to the magnetic detector can be prevented.

Further, the characteristic configuration of the sensor unit according to the present invention is a first output terminal that outputs a detection result of a magnetic detector that detects the magnetic flux density of a magnetic flux generated around a conductor through which a current flows, and a detection result of the magnetic detector. A second output terminal that is used to correct the temperature characteristics included in the above and outputs the detection result of the temperature detection unit that detects the temperature in the package in which the magnetic detection unit is arranged, the magnetic detection unit, and the temperature detection. The point is that it is provided with a pair of positive and negative power supply terminals that supply power to the unit.

With such a feature configuration, the temperature detection result used for correcting the temperature characteristic (temperature characteristic of the magnetic detector) included in the detection result of the magnetic detector can be used for purposes other than the correction. Can be done. Therefore, for example, when the application requires temperature detection in addition to magnetic flux density detection, it is not necessary to separately provide a temperature sensor, so that the configuration can be inexpensive.

It is a block diagram which shows typically the structure of the energization control system. It is a figure which shows typically the structure of a sensor unit. It is a figure which shows an example of the map data stored in a map. It is a figure which shows the temperature change of a package.

Hereinafter, the energization control system 1 and the sensor unit 100 of the present embodiment will be described. FIG. 1 is a block diagram showing the configuration of the energization control system 1. As shown in FIG. 1, the energization control system 1 includes a sensor unit 100 and a control unit 200.

The sensor unit 100 is configured to measure the current to be measured flowing through the conductor 2 and the temperature of the sensor unit 100. Here, when a current flows through the conductor 2, a magnetic field is generated with the conductor 2 as the axis according to the magnitude of the current, and a magnetic flux is generated by the magnetic field. The sensor unit 100 detects the magnetic flux density of such a magnetic flux, and measures the current (current value) flowing through the conductor 2 based on the detected magnetic flux density.

FIG. 2 shows a perspective view of the sensor unit 100. In order to facilitate understanding, the direction in which the conductor 2 through which the measured current flows extends is defined as the direction A, and the directions orthogonal to this direction A are defined as the direction B and the direction C, respectively.

Here, the conductor 2 is provided so as to penetrate the annular core 3. The conductor 2 is a frequency conversion that converts at least one of the frequencies of the three-phase rotary electric machine 4 (see FIG. 1) and the electric power input to the three-phase rotary electric machine 4 and the electric power output from the three-phase rotary electric machine 4. It is used as a bus bar that electrically connects the vessel 5 (see FIG. 1). In the example of FIG. 1, a three-phase motor is shown as the three-phase rotary electric machine 4. Therefore, the frequency converter 5 corresponds to an inverter that converts DC power output from the battery 90 or the like into AC power. The conductor 2 supplies the voltage and current converted into AC power by such an inverter to the three-phase motor. Therefore, in the present embodiment, the sensor unit 100 targets the current flowing through the plurality of conductors 2 as the object to be measured.

Further, the conductor 2 is connected in series to the output terminal of the inductor 7 of the voltage converter 6 that boosts and outputs a predetermined input voltage. The predetermined input voltage is a voltage output from the battery 90. The voltage converter 6 corresponds to a DC / DC converter that boosts this voltage by a chopper method. The conductor 2 is used to connect the inductor 7 included in the voltage converter 6 and the diode 8 in series.

Returning to FIG. 2, the core 3 has an opening portion 11 in a part of an annular shape and is composed of a magnetic material. The core 3 according to the present embodiment is formed by laminating flat plates made of a metal magnetic material having a groove portion 12 in the A direction of FIG. The metal magnetic material is a soft magnetic metal, and corresponds to an electromagnetic steel plate (silicon steel plate), permalloy, or the like. As such a magnetic material, for example, a non-oriented electrical steel sheet can be used. Of course, other electromagnetic steel sheets can also be used. The core 3 is constructed by punching out such a metal magnetic material. The conductor 2 described above is inserted into the groove 12 of the core 3. This makes it easier for the core 3 to collect the magnetic flux generated around the conductor 2.

The sensor unit 100 is provided in the opening portion 11 of the groove portion 12. The sensor unit 100 has a magnetic detection unit 21, a temperature detection unit 22, a correction unit 23, and an output unit 24. The magnetic detector 21 detects the magnetic flux density of the magnetic flux generated around the conductor 2 according to the current flowing through the conductor 2 of the electric device 300. In the present embodiment, the electric device 300 corresponds to the three-phase motor as the three-phase rotary electric machine 4 described above, the inverter as the frequency converter 5, and the DC / DC converter as the voltage converter 6. The magnetic detector 21 detects the magnetic flux density generated in the opening portion 11 of the groove portion 12. The magnetic detector 21 may use a known Hall IC or magnetoresistive sensor (MR element).

The temperature detection unit 22 detects the temperature inside the package 25 in which the magnetic detection unit 21 is arranged. The sensor unit 100 is configured with the magnetic detector 21 enclosed in a known mold. Therefore, the "package 25 in which the magnetic detector 21 is arranged" corresponds to the mold of the sensor unit 100. For example, when the sensor unit 100 is configured to have a case of a predetermined size, the package 25 corresponds to such a case. The temperature detection unit 22 is integrally configured with the magnetic detection unit 21 so that the temperature inside the package 25 can be detected. In particular, since it is preferable to detect the temperature in the vicinity of the magnetic detector 21 in the package 25, the temperature detector 22 may be arranged adjacent to the magnetic detector 21 in the package 25.

The correction unit 23 corrects the temperature characteristics included in the detection result of the magnetic detection unit 21 based on the temperature detected by the temperature detection unit 22. As is known, the Hall IC and the magnetoresistive sensor (MR element) used as the magnetic detector 21 have a temperature dependence on the detection result. Therefore, the detection result of the magnetic detector 21 fluctuates according to the environmental temperature, and when the accuracy is required for the detection result of the magnetic detector 21, it is necessary to correct the amount of temperature fluctuation due to the operating environment temperature. The temperature characteristic that defines the temperature dependence of the magnetic detection unit 21 is stored in the correction unit 23 in advance, and the correction unit 23 uses the temperature detected by the temperature detection unit 22 and the temperature characteristic to obtain the magnetic detection unit 21. The detection result of is corrected. As a result, the amount of temperature fluctuation can be removed from the detection result of the magnetic detection unit 21, and the detection result with high accuracy can be used.

The output unit 24 outputs temperature information indicating the temperature detected by the temperature detection unit 22. The temperature information is an electric signal obtained from the detection result of the temperature detection unit 22.

The sensor unit 100 according to the present embodiment is configured to include four terminals. The four terminals are a first output terminal 26, a second output terminal 27, and a pair of positive and negative power supply terminals 28 and 29. The first output terminal 26 outputs the detection result of the magnetic detector 21. The second output terminal 27 outputs the detection result of the temperature detection unit 22 used for correcting the temperature characteristic included in the detection result of the magnetic detection unit 21. The pair of power supply terminals 28 and 29 are positive and negative power supply terminals that supply power to the magnetic detection unit 21 and the temperature detection unit 22. In FIG. 2, four terminals are shown side by side in the order of the first output terminal 26, the second output terminal 27, and the pair of power supply terminals 28, 29, but this arrangement is not particularly limited. Absent.

These four terminals are soldered to electrodes provided on a substrate (not shown). The first output terminal 26 and the second output terminal 27 are connected to the control unit 200, which will be described later, via the electrodes of the substrate. The pair of power supply terminals 28, 29 are connected to a power supply line provided on the board. Of course, all four terminals may be configured to be connected to the control unit 200.

Returning to FIG. 1, the control unit 200 has a control unit 31 that controls the current flowing through the heating element 9 of the electric device 300 based on the temperature information. The electric device 300 corresponds to a three-phase motor, an inverter, and a DC / DC converter in this embodiment. The heating element 9 is a component that generates heat when an electric current flows through it. In the present embodiment, the heating element 9 corresponds to a switching element included in the inverter or a switching element included in the DC / DC converter. Specifically, the transistor Q and the diode D of the inverter and the DC / DC converter correspond to each other.

When the control unit 31 controls the current flowing through the three-phase motor, the control unit 31 first determines that the current value of the current flowing through each bus bar has been kept substantially constant for a predetermined time. The bus bar through which the current of the current value indicating the largest value among the current values of the current flowing through each bus bar flows is specified. In this embodiment, three bus bars are provided. Therefore, the sensor unit 100 is provided in each bus bar, and the detection result of the magnetic detector 21 is transmitted from each sensor unit 100. The control unit 200 calculates the current value for each bus bar using the detection result of the magnetic detector 21. This calculation result is transmitted to the control unit 31.

For example, each phase current of a three-phase motor is a current composed of sine waves having a predetermined phase difference from each other. However, when the motor is locked (when it cannot rotate), each phase current becomes a direct current (a direct current including a predetermined pulsation) instead of a sine wave. Such a state corresponds to the above-mentioned state in which a substantially constant state continues for a predetermined time. By the way, as an example of when the motor locks, for example, when using a three-phase motor as a power source for a vehicle, even if the vehicle tries to overcome a high step, it cannot be overcome or it cannot proceed further due to an obstacle. The state etc. can be mentioned.

The determination that "a nearly constant state has continued for a predetermined time" is determined by, for example, the difference between the maximum current value and the second largest current value among the current values of the currents flowing through the plurality of bus bars. The state where the threshold value is exceeded may be continued for a predetermined time from a certain point in time, or the maximum current value among the current values of the currents flowing through the plurality of bus bars is from a certain point in time to a predetermined time. It may be continued within a preset range. When the control unit 31 determines that the current value of the current flowing through each bus bar has been kept in a substantially constant state for a predetermined time, the control unit 31 has the largest current value of the current flowing through each bus bar during the continuation of the constant state. Identify the busbar through which the current of the current value indicating the value flows.

Next, the control unit 31 estimates the temperature rise value of the switching element that controls the current flowing through the specified bus bar based on the temperature information. The specified bus bar is a bus bar through which a current having a current value indicating the largest value flows as described above. The switching element that controls the current is a transistor Q among the switching elements included in the inverter that allows the current to flow through the specified bus bar. The temperature rise value is a temperature difference that rises with respect to a reference temperature (for example, 25 ° C.).

Here, the temperature information is transmitted to the control unit 31 from the temperature detection unit 22 of the sensor unit 100. This temperature information is the temperature inside the package of the sensor unit 100 (particularly the temperature in the vicinity of the magnetic detector 21). Therefore, the switching element of the inverter and the sensor unit 100 are arranged in a state where the distance between them is short, but the temperature of the switching element is not equal to the detection result of the temperature detection unit 22.

Therefore, the control unit 31 stores in advance a map showing the relationship between the temperature information stored in advance and the temperature rise value of the heating element 9, and combines the map with the temperature information transmitted from the sensor unit 100. The temperature of the heating element 9 is estimated based on this. An example of such a map is shown in FIG. This map defines the relationship between the temperature indicated by the temperature information and the temperature rise value of the switching element. Such a relationship may be acquired in advance by an experiment or the like and stored as a map in the map storage unit 32 in the control unit 200. The control unit 31 may estimate the temperature of the heating element 9, that is, the switching element, by using such a map and the detection result of the refrigerant temperature sensor that measures the temperature of the refrigerant that cools the electric device 300.

Next, the control unit 31 controls the operation of the heating element 9 based on the estimation result. That is, when the estimated temperature rise value is equal to or higher than a preset value, the on-duty of the switching element is limited. As a result, the on-duty of the switching element that is generating heat is throttled, so that the current flowing through the switching element can be reduced. Therefore, it is possible to reduce the amount of heat generated by the switching element.

Similarly, when the control unit 31 controls the current flowing through the switching element of the DC / DC converter, the control unit 31 estimates the temperature rise value of the inductor 7 based on the temperature information, and the estimated temperature rise value. Limits the on-duty of the switching element when is greater than or equal to a preset value. Also in this case, the control unit 31 may estimate the temperature rise value of the inductor 7 by using the map stored in the map storage unit 32. When this temperature rise value is equal to or higher than a preset value, it is predicted that an excessive current is flowing through the transistor Q of the DC / DC converter, so that the control unit 31 throttles the on-duty of the transistor Q. It is good to control it like this. As a result, the current flowing through the transistor Q can be reduced, so that the amount of heat generated by the transistor Q can be reduced.

Further, when the temperature in the package 25 indicated by the temperature information reaches a preset reference temperature, the control unit 31 calculates the magnetic flux related to the magnetic flux density to be detected by the sensor unit 100 that outputs the temperature information. It can also be configured to regulate the flow of the resulting current. The temperature information is information transmitted from the temperature detection unit 22 of the sensor unit 100 as described above, and is information indicating the temperature inside the package of the sensor unit 100 (particularly the temperature in the vicinity of the magnetic detection unit 21). "Regulating the flow of the current that generates the magnetic flux related to the magnetic flux density that is the detection target of the sensor unit 100 that outputs the temperature information" means that the sensor unit 100 detects the magnetic flux density caused by the current flowing through the bus bar. Means that the current value of the current flowing through the bus bar is limited to be small, and when the sensor unit 100 detects the magnetic flux density caused by the current flowing through the inductor 7 of the DC / DC converter, the current flowing through the inductor 7 It means that the current value of is limited to be small.

Therefore, when the temperature inside the package 25 indicated by the temperature information transmitted from the sensor unit 100 that detects the magnetic flux density due to the current flowing through the bus bar reaches a preset reference temperature, the control unit 31 reaches. A preset reference for the temperature inside the package 25 indicated by the temperature information transmitted from the sensor unit 100 that controls to throttle the on DUTY of the switching element of the inverter and detects the magnetic flux density caused by the current flowing through the inductor 7. When the temperature is reached, the on-DUTY of the transistor Q of the DC / DC converter is controlled to be throttled.

FIG. 4 shows an example of the temperature change in the package 25 when the current is controlled based on the temperature in the package 25 indicated by the temperature information. As shown in FIG. 4, it is assumed that the magnetic detector 21 starts detecting the magnetic flux density at time t0. Along with this, the temperature inside the package 25 rises.

When the temperature in the package 25 reaches the reference temperature T1 which is the threshold value at the time t1, the control unit 31 controls so as to throttle the on-duty of the switching element to be controlled as described above. As a result, the current value of the current that is the basis of the magnetic flux related to the magnetic flux density that is the detection target of the magnetic detector 21 is controlled to be small, and the temperature inside the package 25 is lowered. At this time, as shown in FIG. 4, when the temperature inside the package 25 reaches the release temperature including the predetermined temperature T2 smaller than the reference temperature T1 (time t2), the control unit 31 releases the regulation of the current. It can be configured as follows. By configuring so as to have hysteresis in this way, malfunction can be prevented.

[Other Embodiments]
In the above embodiment, the three-phase rotary electric machine 4 has been described as a three-phase motor, but it may be a generator. In this case, the frequency converter 5 functions as a rectifier circuit that rectifies the electric power output by the generator, and the switching element corresponds to the diode D. It is possible to apply the present invention even with such a configuration.

In the above embodiment, the voltage converter 6 has been described as a DC / DC converter for boosting, but it may be a DC / DC converter for step-down or a DC / DC converter for inverting. .. Of course, it may be a DC / DC converter for buck-boost.

In the above embodiment, when the control unit 31 controls the current flowing through the switching element of the inverter, the switching of the inverter is performed when the estimated temperature rise value of the switching element of the inverter is equal to or higher than a preset value. When limiting the on-DUTY of the element and controlling the current flowing through the switching element of the DC / DC converter, the DC / DC converter when the estimated temperature rise value of the inductor 7 is equal to or higher than a preset value. It has been described as limiting the on-DUTY of the switching element of. The above-mentioned "preset values" may be the same values or different values (for example, "preset first value" and "preset second value").

The present invention may be used in the current control system for controlling the energization of the heating element.

1: Energization control system 2: Conductor 4: Three-phase rotary electric machine 5: Frequency converter 6: Voltage converter 7: inductor 9: Heat generator 21: Magnetic detector 22: Temperature detector 23: Correction unit 24: Output unit 25 : Package 26: 1st output terminal 27: 2nd output terminal 28: Power supply terminal 29: Power supply terminal 31: Control unit 100: Sensor unit 200: Control unit 300: Electrical equipment

Claims (4)

A magnetic detector that detects the magnetic flux density of the magnetic flux generated around the conductor according to the current flowing through the conductor of the electrical equipment, and a temperature detector that detects the temperature inside the package in which the magnetic detector is arranged. A sensor unit having a correction unit that corrects the temperature characteristics included in the detection result of the magnetic detection unit based on the detected temperature, and an output unit that outputs temperature information indicating the detected temperature.
A control unit having a control unit that controls a current flowing through a heating element of the electric device based on the temperature information.
Equipped with a,
The control unit estimates the temperature of the heating element based on a map showing the relationship between the temperature information stored in advance and the temperature rise value of the heating element and the temperature information transmitted from the sensor unit. , estimation result to the conduction control system that controls the operation of the heating element based. The conductor electrically connects the three-phase rotary electric machine and a frequency converter that converts at least one of the electric power input to the three-phase rotary electric machine and the electric power output from the three-phase rotary electric machine. There are multiple bus bars to
The heating element is a plurality of switching elements included in the frequency converter.
When the control unit determines that the current value of the current flowing through each bus bar has remained substantially constant for a predetermined time, the current value of the current value indicating the largest value among the current values of the current flowing through each bus bar. The temperature rise value of the switching element that controls the current flowing through the specified bus bar is estimated based on the temperature information, and the estimated temperature rise value is equal to or higher than a preset value. The energization control system according to claim 1, wherein the on-DUTY of the switching element is limited in the case of the case. The conductor is connected in series to the output terminal of the inductor of the voltage converter that boosts and outputs a predetermined input voltage.
The heating element is a switching element included in the voltage converter.
The control unit estimates the temperature rise value of the inductor based on the temperature information, and claims to limit the on-DUTY of the switching element when the estimated temperature rise value is equal to or higher than a preset value. Item 2. The energization control system according to item 1 or 2. When the temperature inside the package indicated by the temperature information reaches a preset reference temperature, the control unit generates a magnetic flux related to the magnetic flux density to be detected by the sensor unit that outputs the temperature information. The energization control system according to any one of claims 1 to 3 , which regulates the flow of electric current.

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